Extent of post-juvenile moult in wintering Common Chiffchaffs Phylloscopus collybita is related to indices of individual quality

摘要: Inter-individual differences in the extent of post-juvenile moult migratory birds are usually attributed to energetic or time constraints that related their different geographic origins. In addition, recent research has stressed importance food availability and strategies birds. Consequently, individual quality foraging ability will affect both body condition. We thus hypothesized these two variables could be influenced by same factors correlated winter. tested whether was associated with condition (body mass, muscle fat scores) (tarsus bill length) forty-six male Common Chiffchaffs Phylloscopus collybita wintering Mediterranean area. found no correlation between mass. Nevertheless, longer bills higher scores did have better moulted more flight feathers. The number contour feathers were increased as season progressed, whereas mass varied on a daily basis. Our results support idea influences winter performance suggest juvenile enable some individuals improve performance.